DESCRIPTION: (Applicant's Description) The major objective of this proposal is to evaluate the influence of situational/contextual and trait factors and the role of individual differences in nicotine-dependence susceptibility in adolescent smoking. Over 90% of smokers begin smoking before the age of 18, yet little is known about what makes adolescents vulnerable to the initiation of smoking and susceptible to tobacco dependence. Psychological traits including impulsivity, aggressiveness, negative affectivity, and attention-deficit are associated with a greater incidence of tobacco use, yet little is known about how these factors contribute to the initiation and maintenance of tobacco use in adolescents. The aims of this project are directly related to the NIH's research priority on psychological, physiological, and pharmacological determinants of adolescent cigarette smoking as well as the initiative's focus on temperament and neuropsychiatric factors. Two hundred and forty adolescents entering the 9th grade (80-never smokers, 80-experimental smokers, 80-regular smokers) will be signaled to fill out a diary twice an hour indicating their location, activities, social context, and whether they had smoked or consumed food and other substances. They will be asked to report on their moods and their degree of hunger and urge to smoke. In addition, heart rate will be recorded continuously to determine its role as a discriminative stimulus for smoking as well as an index of the physiological response to cigarette smoking. Each group will comprise approximately equal numbers of adolescents with externalizing and internalizing behavior patterns and healthy controls. Salivary cotinine will be used to validate diary reports of cigarette smoking. The self-monitoring will be done on two school and two weekend days. This 4-day sequence will be repeated six times over three years. Subsamples of these adolescents, including 24 with attention-deficit hyperactivity disorder (ADHD) and externalizing behavior problems, 24 with ADHD and internalizing behavior problems. and 24 healthy controls will be studied in the laboratory to determine the effects of nicotine (patch) on subjective, behavioral. autonomic, and adrenergic measures. Analyses will model the stimuli and cues associated with smoking behavior and urges and how these change over time, as well as examine the effects of cigarette smoking on subjective, behavioral, and psychophysiological responses of adolescents in natural settings and in the laboratory. We will also determine the role of trait and behavioral characteristics (conduct/impulse, negative affectivity, and attention-deficit disorders) and gender in the above relationships. The long range goal is to utilize the information obtained on susceptibility to smoking in adolescents in designing more effective smoking prevention and cessation programs.